My youngest son benefited SO much from the Time4Learning homeschool curriculum during middle school. We used it as our core for language arts and math for 5th-8th grades and as our core for social studies in 7th grade and as a supplement for science and social studies the remaining years. I was THRILLED to learn that they are opening up their curriculum through 12th grade starting this fall!! If you haven't heard about the new high school program, here's the link for more info: Homeschooling High School Courses - Time4Learning
If you've never used T4L and have any questions about it, feel free to PM me!